Semiconductor devices find application in a wide variety of electronic components and systems. Useful semiconductor devices for radio frequency (RF) and high-speed applications may include heterojunction field effect transistors (HFET's), metal-insulator field effect transistors (MISFET's), junction field effect transistors (JFET's), and bipolar devices (e.g. bipolar junction transistors (BJT's) and heterojunction bipolar transistors (HBT's)). Semiconductor devices may be formed from group-III nitride (III-N) semiconductors. Semiconductor devices may include ohmic contacts such as drain/source contacts, gate contacts, emitter/collector contacts, and control electrodes such as gate contacts or base contacts. Accordingly, there is a need for semiconductor devices with manufacturable, high performance, and reliable ohmic contacts and control electrodes (e.g., drain/source contacts, gate contacts, emitter/collector contacts, and base contacts) as well as methods for making such semiconductor devices.